This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. During the reporting period, in other work we found that patients with PTSD do not show normal conditioned inhibition which means we have an objective measure of one of the core symptoms of PTSD, namely the inability to feel safe. We have set up the AX+, BX- in rhesus monkeys at Yerkes and have found good safety signal learning in 3 control and 1 maternally separated monkeys. In the other two separated monkeys they failed show inhibitory learning. This work will now continue in 34 more monkeys funded by a Challenge grant for which I hired a new non-human primate technician, to do this work. She has now completed testing on 12 more monkeys and is almost done with another 6 monkeys.